Knife sharpener

ABSTRACT

A sharpening or abrasive device comprising a frame with supply and take-up assemblies for containing a replacement supply of abrasive sheet material and holding an exposed portion of the abrasive sheet which wraps around the frame, portions of the frame engaging the exposed abrasive sheet providing a variety of configurations for conforming the abrasive surface with different cutting edges or surfaces to be sharpened or abraded and for providing an abrasive surface on which the device rests.

United States Patent n 1 Hughes KNIFE SHARPENER [76] Inventor: Austin L. Hughes, 193 Charter Oak,

San Francisco, Calif. 94124 22 Filed: May19,1971

[21] Appl.No.: 144,923

[52] US. Cl ..5l/36l [51] Int. Cl. ..B24d 17/00 [581 Field of .5 l/359 36l [56] References Cited UNITED STATES PATENTS 2,435,335 2/1948 Andrews ..5 H361 1,274,513 8/1918 Cramer ..5 H361 752,475 2/1904 Smith ..5l/361 FOREIGN PATENTS OR APPLICATIONS 677,068 8/1952 Great Britain ..5 U361 [451 Apr. 17,1973

683,261 6/1930 France ..5l/361 456,289 2/1928 Germany ..5l/36l Primary Examiner-Othell M. Simpson AttorneyFryer, Tjensvold, Feix, Phillips & Lempio ABSTRACT A sharpening or abrasive device comprising a frame with supply and take-up assembliesfor containing a replacement supply .of abrasive sheet material and holding an exposed portion of the abrasive sheet which wraps around the frame, portions of the frame engaging the exposed abrasive sheet providing a variety of configurations for conforming the abrasive surface with different cutting edges or surfaces to be sharpened or abraded and for providing an abrasive surface on which the device rests.

6 Claim, 3 Drawing Figures F'ATENTED 71975 3.727, 351

INVENTOR. FIG 3 I AUSTIN L. HUGHES are typical prior art devices commonly employed for sharpening knives but after limited use, their abrasive surfaces become disfigured or worn away. Thus, they do not remain suitable for maintaining a cutting edge of selected configuration. Many knives must have a straight cutting edge while others such as linoleum knives for example, are designed with curved cutting edges which often do not conform with the abrasive surfaces of such known devices.

Also, such prior art sharpening or abrasive devices are normally hand-held so that one must use both hands to sharpen knives or other such tools.

The present invention is particularly contemplated as providing an improved means for sharpening variously configured cutting edges of knives and the like while overcoming disadvantages of the type described above. However, the present invention is not limited to such a function.

The. device of the present invention comprises a frame which is adapted to store abrasive sheet material and permit replacement of the abrasive surface.

In addition, the outer surface of the frame which engages the abrasive sheet or belt has a variety of shapes so that one portion or another of the abrasive surface may be adapted to such differently configured cutting edges. Thus, the present invention facilitates the sharpening of various cutting edges while maintaining the selected configuration of each.

The frame is also designed so that abrasive material is arranged upon its opposite surfaces. This feature permits many knives and other tools to be sharpened in a one-handed operation. Regardless of the surface which is selected for use, the opposite abrasive surface rests on the supporting surface of a table for example, and prevents movement of the frame while the cutting edge is rubbed along its exposed abrasive surface.

Preferably, one surface of the frame is flat so that the device of the present invention is adapted for sharpening straight cutting edges as well as for sanding or polishing generally flat surfaces.

However, it will be apparent that within the scope of the present invention, the surfaces of the frame which engage the abrasive material may be selected to conform with a wide variety of surface configurations.

Advantages of the present invention in addition to those set forth above are made apparent in the following description having reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a device embodying the present invention;

FIG. 2 is a side view of the device of FIG. 1; and

FIG. 3 is a view of the device taken along section line III-III as indicated in FIG. 2 while illustrating the arrangement of abrasive sheet material upon a frame of the device.

A device constructed according to the present invention and illustrated in the drawing comprises a frame 11 adapted for mounting an elongaged sheet 12 of abrasive material. The frame also contains an additional supply of the abrasive sheet material so that the exposed abrasive surface may be readily replaced.

The frame forms internal cavities 13 and 14 for respectively receiving a supply roller 16 and a take-up roller 17. Each roller includes a shaft 18 penetrating opposite ends of the frame 11. A flat spring or washer l9 and a self-locking wingnut 21 are arranged on the threaded end of each shaft penetrating one end of the.

frame. A turning knob 22 is secured to or integrally formed with the other end of each shaft. A flat spring or washer 23 is arranged between each knob and the opposite end of the frame 1 1.

Each shaft 18 also has a slot 24 at its center for engagement with a tab formed at each end of the sheet or belt of abrasive material for securing the abrasive belt thereto.

The configuration of the frame 1 1 which contains the rollers and engages the abrasive belt is an important feature of the present invention. Surfaces of the frame which engage the outwardly facing abrasive belt are preferably formed with a variety of configurations to conform the abrasive belt surfaces with cutting edges of many different configurations. Also, opposite surfaces of the frame are formed so that the device always rests on a supporting surface by means of a portion of the abrasive belt surface. This feature prevents the device from sliding on the supporting surface while a cutting edge is being rubbed along a surface of the abrasive belt.

To provide these features, the frame has a flat surface 26 which forms the top of the frame when it is in the position illustrated in FIG. 3. The longitudinal edges 2 7 and 28 of the flat surface 26 are slightly rounded to facilitate placement of the belt 12 on the,

frame. The sides 31 and 32 of the frame, as viewed in FIG. 3, are generally flat and taper into cylindrically formed segments 33 and 34 of the frame. The segments 33 and 34 contribute to features of the invention described above while also forming the cavities l3 and 14 which contain the supply and take-up rollers 16 and 17. The frame includes an opening 36 longitudinally arranged between the two segments 33 and 34 to permit the abrasive belt to be coupled with the two rollers and extend around the frame as illustrated in FIG. 3. While contributing to the novel features of the present invention as discussed above, the design of the frame 11 also permits it to be readily and inexpensively formed from suitable materials such as rnetalor plastic, for example.

The frame may formed of separable portions (not shown) if desired to facilitate installation and removal of the abrasive belt with respect to the rollers 16 and 17.

In operation, most of the belt 12 is coiled upon the ing outwardly and coupled with the take-up roller 17, t

for example by means of the slot 241 in its shaft 18. The

wingnuts 21 are tightened so that the spring washers 19 and 23 are drawn against opposite ends of the frame 11. The wingnuts are adjusted so that free rotation of the rollers 16 and 17 tends to be prevented and the belt is snugly held in engagement with the frame while permitting rotation of the rollers by the knobs 22 for replacing the exposed abrasive surface when desired. After the belt is installed on the frame, the take-up roller may be adjusted by its knob 22 to remove any slack in the belt.

With the belt so installed and closely conforming with the frame surfaces 33, 31, 26, 32 and 34 as shown in FIG. 3, the sharpening or abrasive device is ready for use. It can be arranged on a supporting surface in the position illustrated in FIG. 3. The flat abrasive surface supported by the frame portion26 may then be used for example to sharpen straight cutting edges. The abrasive surfaces on the frame segments 33 and 34 engage a supporting surface (not shown) and prevent slipping of the device.

The frame may also be inverted so that the curved abrasive surfaces on the segments 33, 34 and frame sides 31, 32 are exposed to sharpen curved cutting edges such as may be found on linoleum knives, for example. With the device in this position, the abrasive surface supported by the flat frame surface 26 engages the supporting surface and prevents slippage of the device. 7

Because of the replaceable or renewable nature of the abrasive belt, the variously configured abrasive surfaces formed by the frame do not become deformed during use as would be the case with whetstones or abrasive blocks. Thus, for example, the abrasive surface formed on the frame portion 26 remains flat and facilitates the accurate sharpening of straight cutting edges even after substantial periods of use.

When any of the exposed abrasive belt surfaces become sufficiently worn, the exposed portion of the belt-may be rapidly renewed or replaced by means of the knobs 22. The supply roller is first rotated to expose an unused portion of the belt. The take-up roller is then adjusted to take up slack in the belt and hold its newly exposed surface in close conformity with the frame.

While the invention has been described above with reference to a single preferred embodiment, it is believed apparent that modifications to that embodiment are possible, particularly with respect to configuration of the frame surfaces which engage the abrasive material, within the scope of the present invention which is defined by the following claims.

lclaim:

l. A device for providing a replaceable abrasive sur face comprising a frame with a rotatable supply roller and take-up means, an abrasive belt coiled about the supply roller with an exposed end of the belt being wrapped around an external surface of the frame and secured to the take-up means, the external frame surface including a flat portion on one side thereof and a plurality of differently configured surface portions on the opposite side of said frame, said plurality of surface portions being formed by spaced apart cylindrical segments on the frame, one of said segments forming a cavity containing said supply roller, a flat surface portion on each side of the frame tapering respectively into a curved surface of an adjacent one of said clylindrical segments, said flat surface portion and said p uralrty of surface portions each providing suitable support for the device whereby the device may be rested on said flat surface portion to present said differently configured surface portions and the device may also be rested on said cylindrical segments to present said flat surface portion.

2. The device of claim 1 wherein the supply roller is engaged with the frame by spring means tending to prevent rotation of the supply roller so that the abrasive belt remains snugly wrapped about the frame while permitting rotation of the supply roller when desired for replacing the exposed belt portion.

3. The device of claim 2 wherein said take-up means is a roller arranged in a cavity formed by said other cylindrical segment and engaged with the frame by spring means.

4. A device for receiving an abrasive belt and permitting replacement of an exposed portion of the belt as it becomes worn, comprising a frame having a flat surface on one side thereof providing a suitable support I for the frame and a plurality of curved surfaces on the opposite side of the frame which also provide a suitable support for the frame, a rotatable supply roller being mounted on the frame for receiving a coil of the abrasive belt and take-up means arranged on the frame for engaging an exposed end portion of the belt after it is wrapped around said flat and curved frame surfaces, the curved surfaces being defined by cylindrical segments formed on the frame, one of said segments forming an internal cavity for receiving said supply roller.

5. The device of claim 4 wherein the supply roller is engaged with the frame by spring means tending to resist turning of the supply roller means being associated with the supply roller for overcoming resistant force of the spring and turning the supply roller.

6. The device of claim 5 wherein the last said means comprises a knob secured to the supply roller at one end of the frame.

It i 

1. A device for providing a replaceable abrasive surface comprising a frame with a rotatable supply roller and take-up means, an abrasive belt coiled about the supply roller with an exposed end of the belt being wrapped around an external surface of the frame and secured to the take-up means, the external frame surface including a flat portion on one side thereof and a plurality of differently configured surface portions on the opposite side of said frame, said plurality of surface portions being formed by spaced apart cylindrical segments on the frame, one of said segments forming a cavity containing said supply roller, a flat surface portion on each side of the frame tapering respectively into a curved surface of an adjacent one of said cylindrical segments, said flat surface portion and said plurality of surface portions each providing suitable support for the device whereby the device may be rested on said flat surface portion to present said differently configured surface portions and the device may also be rested on said cylindrical segments to present said flat surface portion.
 2. The device of claim 1 wherein the supply roller is engaged with the frame by spring means tending to prevent rotation of the supply roller so that the abrasive belt remains snugly wrapped about the frame while permitting rotation of the supply roller when desired for replacing the exposed belt portion.
 3. The device of claim 2 wherein said take-up means is a roller arranged in a cavity formed by said other cylindrical segment and engaged with the frame by spring means.
 4. A device for receiving an abrasive belt and permitting replacement of an exposed portion of the belt as it becomes worn, comprising a frame having a flat surface on one side thereof providing a suitable support for the frame and a plurality of curved surfaces on the opposite side of the frame which also provide a suitable support for the frame, a rotatable supplY roller being mounted on the frame for receiving a coil of the abrasive belt and take-up means arranged on the frame for engaging an exposed end portion of the belt after it is wrapped around said flat and curved frame surfaces, the curved surfaces being defined by cylindrical segments formed on the frame, one of said segments forming an internal cavity for receiving said supply roller.
 5. The device of claim 4 wherein the supply roller is engaged with the frame by spring means tending to resist turning of the supply roller means being associated with the supply roller for overcoming resistant force of the spring and turning the supply roller.
 6. The device of claim 5 wherein the last said means comprises a knob secured to the supply roller at one end of the frame. 